Teletypewriter system



' Sept. 29, 1936. E. F. WATSON 2,055,557

TELETYPEWRITER SYSTEM Filed June 25, 1955 PERFORATOR ACT LEVER BAIL INVENTOR EJ-T WATSON ATTORNEY iii Patented Sept. 29, 1936 UNITED STATES PATENT OFFICE 1 2,055,567 TELETYPEWRITER SYSTEM Edward Fisk Watson,

Larchmon to American Telephone an pany, a. corporation of New York Application June 25, 1935, Serial No. 28,332 23Claims. (or. 178-531) This invention relates to teletypewriter systems and, more particularly, to high speed transmitter distributors for use in such systems.

Heretofore, in teletypewriter systems employing high speed transmitter distributors, trouble has been caused by the distributor brushes bouncing up out of contact with the segments when the brush arm is brought to a sudden stop. During v the time that the brush is so raised, the communiplate, the cam operates the lever ball which, in turn, closes the contact. This closes a shunt across the communication line thereby maintaining the line closed in case the brush should be stopped so suddenly as to cause it to bounce.

These entscorresponding to the six'units of n segment, and a start segment. brush i 8 wiping on the stop segment cuit i 9 connecting therewith a telecation RS preferably through a central oifice L0. The BS station is provided with the usual sending contacts 20 and receiving printer magnet 28. It will be understood that while a central oiiice CO may be used for corn meeting the local distributor and the remote station RS, the invention is not necessarily limited thereto, and may be readily applied to apr'ivate wire, or direct wire system, wherein a central office is not employed.

eight insulated segments which include A tape transmitter assembly ranged for make-break operation is t, N. Y asslgnor d Telegraph Com- 22 preferably ar provided with six contact tongues 26 pivotally mounted on engages either a spacing contact 29 or a marking contact 36, the latter being connected by leads 3| with the segments of the outer ring i3 corresponding to the six units of from the drawing that when a its marking contact It will be observed tongue 26 engages 3B, the line is connected with a code.

the corresponding segment of commutator ring E3. The spacing contacts 29 are always in the opened condition. The opposite end of each tongue 26 is provided with a tip 34 of suitable electrical insulating materialwhich is adapted to engage a bifurcated end portion 35 of a of a three-prong contact lever 3'! horizontal prong 36 that is vformed with a second prong 38, substantially a horimntal extension extending of the pr M. prongs 38 is formed projecting vertically upward into of the tape.

perforator.

ong 36, and a third prong 39 transversely in a downward direction The free end of each of the into the shape of a pin M for the perforations The distances between the tape pins with the distances in the tape by the to the right of the lower portions of the prongs 39 is a contact lever bail pivotally mounted ona shaft 45 and provided.

on the lower left end thereof with a projection ii normally engagin ing through the rig lever 49 mounted on an adjustable pin iii extendht-hand end of an operating a vertical pivot 18. The con tact lever bail is normally urged in a clockwise direction by a spring 53.

When the contact lever bail is actuated by the operating lever to the left in a manner to be described hereinafter, the

prongs 39 re moved in thereby rotating levers 3? a clockwise direction about the shaft ditto withdraw the pins M beneath the surface of the tape, and, at the same time, to cause the prongs 36 to be moved upwardly to actuate the tongues into engagement with their spacing contacts 29.

It will be seen from the 35 are normally biased in drawing that the prongs a downward direction by springs 5d against actuation by the contact lever bail.

Also pivoted on left of the contact formed with a trans the shaft #0 to the extreme tically downward for engagement with the contact lever bail and a horizontal prong 51 provided on its free end with a pivotal feed pawl 58. The feed-lever 55 is normally drawn in a counterclockwise direction by a spring 59. The pawl is normally urged by a spring 62 into engagement with a ratchet wheel 63 fixedly carried on one end of a shaft 64 which is provided on its opposite end with a feed wheel 65 arranged with suitable teeth for projection into the spaced perforations provided longitudinally in the central portion of the tape to efiect the advancement thereof. The position of the feed pawl with re= spect to the ratchet is determined so that a downward movement of the prong 51 under actuation of the contact lever bail does not permit the feed pawl to engage the ratchet to advance the tape until the six tape pins 44 have been drawn below thetape surface by a leftward movement of the contact lever bail as previously explained. In this manner it is made certain that the tape is not advanced before the withdrawal of the pins M therefrom to obviate a tearing of the tape.

In setting up combinations in the transmitter for transmission by the distributor, the contact lever bail is normally biased to the right by the spring 53 out of engagement with the prongs 39. This allows the springs 54 attached to the prongs '36 to cause a counter-clockwise rotation of the contact levers 31 to move the pins it upwardly into engagemen 'with the under-surface of the tape. In this position certain ones of the pins 44 will be accommodated by appropriate code perforations in the tape and, accordingly, will be projected thereinto. Any additional movement of a particular contact lever 3'! occasioned by the projection of its pin 44 into its tape perforation will cause the prong 36 of that lever to move downwardly a corresponding amount thereby rotating the contact tongue 26 from the spacing contact 29 into engagement with the marking contact 39. Obviously, the absence of perforations in the tape will block the pins M to prevent any additional movement of the levers 3i and, hence, the contact tongue 26 associated with a blocked lever 31 will be retained on the spacing contact 29. It will be readily understood, therefore, that when there is a perforation in the tape the corresponding will move into engagement with its marking contact 39 thereby connecting one side of the line to the segment of commutator it with which that contact is associated to transmit amarking impulse over the line. When a pin 5% is blocked, due to the absence of a tape per foration, the contact tongue corresponding therecontact tongue to remains'on its spacing contact 29, and the segment of the, commutator l3 associated'with the latter will cause a spacing or no-current impulse to be transmitted 'over the line.

The brush 18 comprising metallic portions for wiping over the commutator rings i2 and i3 is mounted on one end of a main drive shaft 68 having a gear wheel 69 fixed thereon in mesh with a worm 19 carried on a shaft H which is connected through a friction clutch 12 to a motor 13 employed to. drive the main shaft 68. On the lowermost portion of the shaftt is fastened a tape reed operating cam Id provided with a raised cam portion 15 which engages the left end of the operating lever 49 pivoted at 18 to actuate the 7 contact lever bail. The raised cam portion is prelever bail also actuates the feed ment of the outer commutator ring l3 after each revolution, the lever 49, which heretofore was riding on the low portion of the cam 14, begins now to engage the raised cam portion 15 with the result that the contact lever bail is started in its movement to left on pivot 45. The'continuation of the latter movement pushes the prongs 39 in a clockwise direction thereby causing the prongs 36 to disengage from the marking contacts 30 any tongues that may have been in engagement therewith and to move them into touch with the spacing contacts 29. As previously seen, the contact lever 55 and, in addition, effects the withdrawal of the pins M from the tape perforations before the tape is advanced. With this kept in mind, it will be understood that as the raised cam portion 15 commences to engage the lever 49, the prong 5'i ofithe lever 55 begins tomove downward to cause the pawl mounted thereon to start the rotation of the ratchet. When the lever 39 est point of the cam portion 15, the ratchet is moved an angular distance to an amount equivalent to the distance between contiguous teeth of the ratchet. Accordingly the tape is advanced to set up the code unit combination for the next character to be transmitted.

In the normal operation of the transmitter distributor, it occurs frequently that there is a difference between the rate at which the character units are transmitted and that at which the tape is fed from the perforator. Since the tape is fed directly from the perforator to the transmitter, it will be evident that, if for any reason the perforator operation is interrupted, the transmitter will use up all of the slack in the tape and thereafter proceed to damage the feed holes used with the feed wheel for advancing the tape, unless a provision is made to stop the transmitterdistributor automatically. For the purpose, therefore, of taking care of the difference between the rates of operation-of the transmitter distributor and the perforator, there is fixedly mounted on the main drive shaft intermediate the gear wheel 69 and the tape feed operating cam 1d a stop cam 19 formed with a peripheral shoulder 80. Associated with the stop cam is a stop arm 81 pivoted at 82 and normally having one end held in engagementwith the periphery of the stop cam by a spring '83. The opposite end of the stop arm is operatively associated with a magnet 87 which is employed to rotate the stop arm about its pivot to move the former out of engagement with the stop cam periphery. Battery is connected through the winding of the magnet by a lead 83 to an electrical contact 89, which is opened and closed under control of an automatic stop lever 99 projecting between the transmitter and perforator so that the tape passes thereunder and supported in vertical slots provided in upright members 95, 9E. The contact 89 is also connected through a manually operated switch 92 to ground 93.

After the motor 53 has been started by closing the switch in its power supply circuit, the manual switch 92 is closed to complete an energization circuit for the magnet 81. This circuit may be traced from ground 93, switch 92, contact 89 when closed, lead 88, winding of the magnet 81 to 'battery and ground. The magnet operates to disengage the stop arm from the stop cam to permit the rotation of'the main the perfcrator continues to operate, the tape being fed therefrom will have sufficient slack to allow the stop lever 90 to rest on the upper membef reaches the highdrive shaft. So long as :5 brush bouncing,

of contact 69,, thereby retaining the latter in the closed condition. In the event that the perforator operation is interrupted the to stop the drive shaft distributor brush by holding the main from rotation. In this event, it will be evident that the transmitter is also stopped since it is also driven from the main shaft. It will be understood that the distributor brush will only be stopped on the stop segment of the commutator I3 due to the fact that the shoulder 80 of the stop cam I8. is predeterminedly positioned with respect to the distributor brush to eifect this result.

Inasmuch as the distributor brush rotates at a high speed in transmitting the impulses set up by.

magnet. As a result of the sudden stop. the distributor brush is frequently caused to be disengaged from the stop segment of commutator l3 thereby opening the line circuit and tending to transmit a false space impulse to the receiver of station RS.

In the preferred form, this invention obviates the transmission of the false impulse by closing the line circuit through leads 94, 95 and contact 96 on all occasions when the distributor brush wipes over the central part of the stop segment of commutator ring l3 upon the completion of each character transmission. This is accomplished by mounting a pin 91 in the upper right hand portion of the contact lever ball so that the pin 91 will always eifect the closing or the normally open contact 96 when the lever 49 engages the raised portion 15 on the stop cam 14, the latpart of the stop segment of the commutator I3 in the completion of the transmission ofone character code. Immediately prior to the instant when the stop arm- 6| engages the shoulder 80 of the stop cam 19, the contact 96 is closed. Contact 96 opens before the brush l8 commences to wipe the start segment for the transmission of the next combination 01' code impulses. It is seen, therefore, that when the distributor is stopped on the central part of the stop segment, the line circuit may be closed simultaneous- 1y through either of two paths, first through the "stop" segment, distributor brush, and commutator ring I 2; and, secondly, through the path of leads 94, 95, and'contact 96.

Accordingly, it is evident that the closing of the line circuit through the two paths simultaneously serves to preclude the transmission of a false spacing signal occasioned by the distributor or disengaging; irom the stop segment; since the line circuit closed through the second pathat the time when the brush disengagement is most likely to occur.

What "is claimed is:

0 '1. A teletypewriter system having in combing:

tion a distributor having a segmented face' plate and a rotatable brush adapted to travel over the surface of the face-plate, said distributor being connected to a closed telegraph line, driving means i for causing the brush to travel over the surface brush will always be*- of the face-plate, control means for stopping the movement of the brush, and instrumentalities for preventing the closed line from being uninten tionally opened by reason of the brush bouncing into the air when it is stopped, said instrumentalities including a contact adapted to close a shunt across the closed line whenever the brush is in condition for being stopped. I

2. A teletypewriter system having in combination a high-speed transmitter-distributor having a segmented face-plate and a rotatable brush adapted to travel over the surface of the faceplate, said transmitter-distributor being connected to a normally closed telegraph line, said segmented face-plate having a stop segment, driving means for causing the brush to travel over the surface of the face-plate ata high speed, control means for suddenly stopping the movement of the brush, and instrumentalities for preventing the normally closed line from being unintentionally opened due to the brush bouncing into the air when it issuddenly stopped said instrumentalities including a normally open contact controlled by a cam and adapted to be closed whenever the brush is on the stop segment of the distributor face-plate.

3. Ateletypewriter system having in combination ,a. transmitter-distributor provided with a segmented face-plate and a brush adapted to wipe over'the face-plate, said face-plate comprising a pluralityof segments including a stop segment, a telegraph line circuit connected to the trans; mitter-distributor and normally closed through the stop segment and thebrush, driving means for causing the brush' to wipe over the segments, control means associated with the transmitterdistributor for abruptly stopping the brush when thelatter has reached .the stop segment, and

means controlled by the driving means for shunting the transmitter-distributor on the line circuit to preventthe line circuit from being inadvertently opened due to the brush disengaging the stop segment when the brush is abruptly stopped thereon.

4. A teletypewriter system having in combination a transmitter-distributor provided with a segmented face-plate and a brush to wipe over the segments being desigthetransmitter-distributor telegraph line circuit normally closed through the stop segment and the brush, driving means for causing the brush to wipe over the segments, control means associated with the transmitter-distributor for abruptly stopping the brush when the latter has reached the stop segment, and means operatively conthe face-plate, one of nated a stop segment, being connected to a nected with the driving means for shunting the transmitter-distributor on the line circuit when the brush has been stopped on the stop segment.

5. A teletypewriter tion a transmitter-distributor provided with a segmented face-plate-and a brush to wipe over the face-plate, one of the segments being designated a stop segment, the transmitter-distributorbeing. connected to a telegraph line circuit normally closed through the stop segment and the brush, driving means for causing the brush to :ipe over the segments, control means associated th the transmitter-distributor for abruptly stopping the brush when the latter has reached the stop segment, normally opened electrical contacts connected to the line circuit in parallel with the transmitter-distributor,, means operatively connected to the contacts for effecting an engagement therebetween, and means associated with system having in combines the driving means for actuating the contact means to effect an engagement between the contacts when the brush has been stopped on the stop segment thereby short-circuiting the transmitterdistributor through the contacts.

6. A teletypewriter system having in combination a transmitter-distributor provided with a segmented face-plate and a brush to wipe over the face-plate, one of the segments being designated a stop segment, the transmitter-distributor being connected to a telegraph line circuit normally closed through the stop segment and the driving means for causing the brush to wipe over the segments, control means associated with the transmitter-distributor for abruptly stopping the brush when the latter has reached the stop segment, and means operativeiy connected with the driving means for short-circuiting the transmitter-distributor on the line circuit when the brush has been stopped on the stop segment, the means comprising a normally opened electrical contact adapted to be closed by a cam associated with the driving. means to short-circuit the transmitter-distributor on the line circuit whenever the brush is stopped on the stop segmerit.

'7. In a teletypewriter system, a plurality of concentric commutators, one of the commutators comprising a plurality of segments including a stop segment, a brush for wiping over the commutators, a telegraph line normally closed as the brush wipes the stop segment, a transmitter connected with the segmented commutator, means for actuating the brush and transmitter, and a device operated by the. transmitter for shunting the commutators as the brush wipes the stop segment.

, 8. In a teletypewriter system, a plurality of, concentric commutators, one of the commutators comprising a plurality of segments including a stop segment, a brush for wiping over the commutators, a telegraph line normally closed as the brush wipes the stop segment, a transmitter connected with the segmented commutator, means for actuating the brush and transmitter, means for stopping the actuating means so that the brush stops on the stop segment, and an instrumentality operated by the transmitter for shunting the commutators when the brush is stopped.

9. In a teletypewriter system, a plurality of concentric commutators, one of the commutators comprising a plurality of segments including a stop segment, a brush for wiping overthe commutators, a telegraph line normally closedas the brush wipes the stop segment, a transmitter connected with the segmented commutator, means for actuating the brush and transmitter, and a device for providing a second the line as the brush wipes the stop segment, said device including a normally opened contact con-,

nected in shunt with the commutators and'arranged to be closedby the transmitter as thebrush wipes the stop segment.

' perforator for the tape,

path for closing one of the commutators normally opened contact connected in shunt with the commutators and arranged to be closed by the transmitter when the brush rests on the stop segment. v

11. In a teletypewriter system, a plurality of concentric commutators, one of the commutators comprising a plurality of segments including a stop segment, a brush for wiping over the cornmutators, a telegraph line normally closed when the brush rests on the stop segment, a tape, a a transmitter connected with the segmented commutator including a device for drawing the tape from the perforator, means for actuating the brush and the transmitter, means for stopping the actuating means so that the brush rests on the stop segment,

means associated with the tape for operating the stopping means, and an instrumentality operated by the transmitter for shunting the commutator when the brush is stopped on the stop segment.

12. In combination, a motor, a distributor driven by the motor, the distributor comprising a segmented ring having a stop segment and a brush traversing the ring, a circuit for periodically short-circuiting the serving to close and open the circuit, and means responsive to each traverse of the stbp segment by the brush for operating the contacts. V

'13. In combination, a distributor connected to a communication channel, said distributor having a segmented face-plate, a brush adapted to sweep over the segments of the face-plate seriatim, driving means for driving the brush, a condistributor, contacts tact for shunting the distributor out of the communication channel, and operating means for operatingthe contact.

14.'In combination, a distributor connected to a telegraph line, said distributor having a segmented face-plate, a brush adapted to sweep over the segments of the face-plate seriatim, driving means for driving the brush,a contact for shuntcontact whenever the brush is sweeping over a preassigned segment ofthedistributorface-plate.

16. In combination, a distributor connected to a communication channel, said distributor having a segmented face-plate, a brush adapted/t0 sweep over the segments of the face-plate seriatim, driving means for-driving the brush, a contact for shunting the distributor out of the communication channel, and operating means for alternately and repeatedly opening .and closing the contact.

17. In combination, a telegraph line, said distributor having a segmented face-plate. a brush adapted to sweep over, the segments-of the face-plate seriatim, driving means} foridriving the brush, a contact for closing ashunt path across the telegraph line, and cam actuated means for alternately and repeatedly opening and closing the contact.

18. In combination, a distributor connected to a communication channel, said distributor hava distributor connected to being operatively ing a' segmented face-plate, a brush adapted to sweep over the segments of the face-plate seriatim, said brush being mounted upon a driven drive shaft, a contact for closing a shunt path across the communication channel, and a cam mounted upon said drive shaft for operating the contact.

19. In combination,- a distributor connected to a communication channel, said distributor having a segmented face-plate. a brush adapted to.

sweep over the segments of the face-plate seriatim, saidi brush being mounted upon a driven-drive shaft, acentactfor shunting the distributor out oLthe communication channel, and actuatingmeans' for actuating the contact at predetermined intervals, said actuating means connected to said drive shaft. 20. In combination, a distributor connected to a telegraph line, said distributor having a segmented face-plate, a brush adapted to sweep over the segments of the face-plate seriatim, said brush being mounted upon a driven drive shaft, a contact for periodically closing a shunt path actoss thetelegraph line, and operating means] for periodically operating the contact, said operating means being controlled by said drive shit. I

21.1n combination, a distributor connected to a telegraph' line, said distributor having a segmented face-plate, a brush adapted to sweep the transmission circuit.

over the segments of the face-plate seriatim, said brush being mounted upon a driven drive shaft, stopping means for stopping the brush, a contact for shunting the distributor out of the telegraph line whenever the stopping means operates, and actuating contact, said actuating means being controlled by a cam mounted upon said drive shaft.

22. A teletype'writer system having in combination a distributor including a segmented faceplate, a rotatable brush adapted to travel over the surface of the face-plate, said distributor being connected to a closed communication line, driving means for causing the brush to travel over the surface of the face-plate, control means for causing the movement of the brush to cease, and means responsive to each rotation of the brush for shunting the distributor out of the line.

23. In combination, a transmission circuit, an impulse transmitter connected thereto for sendlng electrical impulses over the transmission circuit, actuating means for actuating the impulse transmitter, starting means for starting the actuating means, stopping means for stopping the actuating means, and means responsive to the operation of the stopping means for preventing an impulse from being unintentionally sent over EDWARD FISK WATSON.

means for operating the 

